Is there an expression or filtering that can be used to report the resolution between Peak A and the next peak that follows in the chromatogram as shown below.

The peak at 2.9 minutes may not always be present in which case the resolution between Peak A and Peak B would need to be reported.

I know how to get the resolution value between Peak A or Peak B and the preceding peak but need to report the value obtained between Peak A and whatever the peak following Peak A is (this could be either a named known peak or an unknown peak). I only want to report the resolution between Peak A and the following peak in the chromatogram in a report.

What resolution calculation are you using? EP, JP, or USP? There is not a built in function in OpenLab CDS for calculating resolution of non-adjacent peaks so this calculation will most likely need to be setup in report template or in a custom calculation file.

the problem is I want to only report the resolution between Peak A and the next peak in the chromatogram. I am able to use the built in features of the software to report resolution between any peak and the preceding peak but i need the resolution between Peak A and the next peak that follows. This next peak may be either an unknown peak or a known peak. As royoboyle indicates I need a Custom calculation or a report method to accomplish this. Do you have any further thoughts?

But i only wanna give u an idea with this.You still need the „official“ answers from agilent.

Found this in google. ( Please verify if this is the formula for your resulution ) Ep, Usp etcBeside the fact that this is from 1997 So the resolution is just ( ( ret A - ret B ) : ( width A - width B ) ) multipy 2

So u Just need The retention time of both components and the width.

Are you using open labs or Chemstation ? Wasnt clear last time, cause you were using chemstation cds and open labs 2.3 in your post.

You can try to put the peak in your table“ add compound“ to method. ( Need to check the exact term )Or you use your integration events, to do the integration for you. ( width reject + area reject )

Idk if you need it in the table but im pretty sure u do. For the calculation.

He said that Openlabs CDS, only can only do it with a custom calculation.

Since you have Open Labs 2.3 you can calculate it, within the Software.

In the end you need to put the Resolution Item in the report.But u still need to know which resulution you need EP or USP .

or you setup a custom calculation.Open your processing window. You find it on the right top side.

Sadly its a bit more complicated in the editor.

One option is either ask here for the formula , or contact your agilent support to do it for you. I suggest you ask them for help. Its way more efficient.

Since you have Open Labs 2.3 you can calculate it then within the Software.

One importand thing at the end.i can send you more information on monday evening.I wanna be honest i never had to calculate it.So i hope it leads you to the right direction.So pls wait for an official answer from agilent.

Re: Resolution between Peak A and next peak in chromtagram Openlab 2.3

reply from camelia in Software - View the full discussion

Hello mr.white

the problem is I want to only report the resolution between Peak A and the next peak in the chromatogram. I am able to use the built in features of the software to report resolution between any peak and the preceding peak but i need the resolution between Peak A and the next peak that follows. This next peak may be either an unknown peak or a known peak. As royoboyle indicates I need a Custom calculation or a report method to accomplish this. Do you have any further thoughts?

Reply to this message by replying to this email, or go to the message on Agilent Community

Start a new discussion in Software by email or at Agilent Community

Following Re: Resolution between Peak A and next peak in chromtagram Openlab 2.3 in these streams: Inbox

This email was sent by Agilent Community either because you are a registered user or because we needed to communicate with you about a specific membership matter.

If you are a registered user you may unsubscribe instantly from Agilent Community, or adjust email frequency in your email preferences

This is a filter. We filter all peaks which have the current peak index (let's say ID = 1) + 1. So we basically filter on the peak index = 2.

.Select(function(f) f.Peak_RetentionTime)

This is what field you want to work with from your list of peaks. In your example, you need to have the peak retention time and peak width.

.first

Is the selection. All the expression before is a list of peaks. Ok, in our case, it's a list of one peak retention time. But it's still a list. We need to select which one. As here we do not really mind about this, we can use first.

You can have these expressions in different cc lines, and then use the cc line identifiers to compute the resolutions (this method is maybe easier),

or

Add these expressions in one line using the formula you have (that method can become a bit cloudy and more difficult to troubleshoot possible mistakes).

This is the custom calculation part. For reporting your results, if you want the resolution of a certain known peaks, you can use a text box, get your cc results, and use a composite group to filter on:

Compound_ Name = "My peak"

If you want all resolution from known peaks, use a table filtered by identified or quantified compounds, and add a column with your cc results.

Hello Pierre, thank you for the cc's you posted. I was not able to write these without an error about trailing Or leading .'s. This could be down to the spacing - AllPeaks .Where (space) or AllPeaks.Where (no space) in the expression? I'm not sure if there needs to be a space or not.

Higoing back and looking at the spacing made me notice that I had made anerror with the syntax - I had written

Select(function(f).Peak_RetentionTime) instead of

Select(function(f). f.Peak_RetentionTime)

No errors now. Just need to work out the nextpart to calculate and report the resolution between Peak A and the followingpeak in the chromatogram. I have used a workaround to achieve this so it is notsuch a pressing matter now but I would still be interested to get it to do whatI wanted and report the resolution between Peak A and the next peak in thechromatogram whether this is an unknown or a named peak. Any further input on this would be happily received but if you don't have time that's fine we can close the post.

In the processing method, enable USP system suitability for all peaks, and reprocess your data. You will need this to calculate the tangent widths for the peaks.

If you want to see this resolution in a single sample report, then you could do something like this:

Add a couple of Fields to the report, the first being peak retention time, the second being the peak tangent width. Select both of them and create a composite group like this.

Repeat this group for each Compound_Name and apply a filter for the name of the first Compound that you want to use. I'm using demo data where the first compound is Ethyl paraben:

Copy this group into the report a second time and change the filter so that it shows results for the second peak you want to report, in my case this is Heptyl paraben, so I now have two groups containing the numbers I want to use to calculate resolution:

Now you need to save these numbers as calculation variables.

Get the properties of the single value field, select the value and click the Fx button to allow you to save the value as a variable.

So, for the retention time for Ethyl paraben, that looks like this:

Repeat this for the other three values for RT and Width.

You can now choose to make these two groups not visible, as we're only using them to populate the variables needed to calculate resolution.

In Ryan's post, you can see the formula for USP resolution, so simply build that in a text box in your report:

Hi Andy, I'm sorry it has taken so long to reply. Thank you for your clear instructions on how to set up a report method to output the resolution value between non adjacent named peaks. I have used this approach and it provides a workaround for the problem I had - to report the resolution between Peak A and the next peak in the chromatogram which could be either a named peak or an unknown peak. As this issue was not addressed by your solution I have not marked your answer as correct although the information you provided was correct and helpful. I hope that makes sense!